To accept it, you just move on with your life. Find the next thing you should do and do it. The more you dwell, the harder it will be to stop dwelling, so just break the cycle and go do anything else.
You will encounter plenty more people who are insistently wrong. Each one will affect you less than the last.
I’d say it’s more like they’re failing upwards. It’s certainly good for AMD, but it seems like it happened in spite of their involvement, not because of it:
AMD didn’t want this advertised or released, and even canned this project despite it reaching better performance than the OpenCL alternative. I really don’t get their thought process. It’s surreal. Do they not want to support AI? Do they not like selling GPUs?